The beat is produced by DJ Premier and contains a sample from I Put a Spell on You by Screamin' Jay Hawkins (a hard song in it’s own right), and many other small or scratched samples, a signature of any great Premo beat.

Although Puff hated the beat, Biggie loved it and both Prim and Biggie went behind Puff’s back in recording this track.

What have the artists said about the song?

After the first album, [Biggie] said, ‘If I blow up and go platinum, I’m going to give you the money you want.’ I charged him $5,000 for ‘Unbelievable,’ then he paid me $30,000 per song on the second one. I can’t be mad at that. That’s a big jump from five grand. ‘Kick In The Door’ almost didn’t make it because I dropped it off to Puff in a 20-minute cassette. Back then when we were dropping beats off, we weren’t burning CDs or flash drives and shit. So I made a beat of that, and gave it to Puff. Then Puff’s office called me later that day saying, ‘Hey, your platinum Biggie plaque came in.’ I went to pick it up that same day. I’m about to leave, then Puff walks out the office and goes, ‘Yo, man. What’s going on? I need you to work on some new stuff for Big.’ I said, ‘I gave him a track today. Remember? I came here and dropped it off.’ He was like, ‘Yeah, but I don’t like that one. That ain’t hot. I need you to come with that Tunnel shit. What you did with ‘Unbelievable.’ Because you ain’t hitting it with this one.’ I said, ‘This shit is hard, yo. Has Big heard it?’ He goes, ‘Big ain’t heard it. I’m going to give it to him, and let him hear it, but you can already count on that not going on the album.’ So I went back thinking of trashing it, and working on another one. Then Biggie calls me later around five or six in the afternoon, and asks, ‘Yo, can you come in tonight so we can lay down the joint?’ I go, ‘But I got to make something.’ Big says, ‘Nah, I want to lay the joint you gave me earlier today.’ I replied, ‘Puff said he didn’t like it.’ Then Big goes, ‘Fuck Puff! I got shit to say, and I got to get at your man Jeru too.’ I said, ‘As long as it’s peaceful, you got to do what you got to do. You’re a man.’ You know, Biggie was hurt by a lot of people he felt like betrayed him when it came to his success. He did what he had to do, but at the end of the day, I wish he were still here.